XRD spectrum of the thermally evaporated PbTe films on a glass substrate: the film is polycrystalline single fcc phase with (200) texture. Standard XRD data of PbTe powder sample from Ref. 12 are also shown at the bottom for comparison.
AFM surface height images of thermally evaporated PbTe films on (a) a soda-lime glass substrate and (b) a Si substrate coated with 400 nm thermal oxide.
dc electrical conductivity of thermally evaporated PbTe films: (a) Conductivity data on a logarithm scale plotted as a function of temperature; lack of linear dependence in the plot suggests that electrical conduction in PbTe is not dominated by the percolation process. (b) Conductivity data plotted as a function of inverse temperature showing thermal activation nature of conduction at high temperature and a weaker temperature dependence at lower temperatures. The black dots are experimental data and the red solid line is linear curve fit of the data at high temperature .
Schematic energy band diagram near a grain boundary and the relevant energy points are: the conduction band edge, the valence band edge, the Fermi level, the band bending on the surface of a grain, and the activation energy of electrical conduction according to the grain boundary conduction channel model.
Refractive index and extinction coefficient of PbTe films are measured using IR ellipsometry.
Absorption coefficient of PbTe films as a function of photon energy. The inset shows plotted against photon energy for the determination of the optical band gap energy .
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